Sorting device for container making machines



1944. N. PELOSI 2,361,960

SORTING DEVICE FOR CONTAINER MAKING MACHINES Filed Jan. 24, 1941 3 Sheets-Sheet l j/ INVENTOR 'Ywm JL. am

ATToNEYS NOV. 7, 1944. v PELQSI 2,361,960

SORTING DEVICE FOR CONTAINER MAKING MACHINES Filed Jan. 24, 1941 3 Sheets-Sheet 2 E974 i7-f/D 1 .5

I26 ATTORNEYS Patented Nov. 7, 1944 soarnve DEVICE FOR CONTAINER MAKING .MACHINES Nicholas Pelosi, Newark, N. J., assignor to American Can Company, New York, N. Y., a -corporation of New Jersey Application January 24, 1941, Serial No. 375,837

6 Claims.

The present invention relates to container making machines in which two or more container parts are secured together with a metal staple and has particular reference to stacking the stapled parts while detecting and discarding un stapled parts.

In securing container parts togetherwith metal staples or stitches, the latter occasionally break during insertion into the parts or are entirely omitted due to faulty operation of the Stitching device. "Ihisomission or breakage of the staples permits the unsecured container parts to become separated or otherwise disarranged and thus they cause trouble in automatic handling and if not detected may become bothersome to packers or customers using the containers in which such unsecured parts are embodied.

'the instant invention contemplates overcoming this diificulty by detecting a staple in the a-ssembledcontainer parts and using the staple as an electric conductor to transmitelectric energy to operate devices which stack the stapled-together parts into a magazine :and which discard the unstapled parts from the machine so that they will be prevented from being subsequently incorporated in the containers.

An object of the invention is the provision of mechanism for detecting metal staples in cont'alnerparts secured together .by such staples wherein the staple is used as a conductor of electric energy so that container parts having no staples at all and those having broken staples may be readily detected.

Another object is the provision of such a detecting mechanism wherein the staple in the assembled container parts or its omission therefrom controls the further disposition of the assembled parts. v

Anotherobject is the provision of a detecting mechanism of this character wherein container parts having required staples are stacked into a magazine while container parts not having staples are prevented from being stacked into the magazine and are discarded from themachine.

Numer us o er objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

' Figure 1 is a top Plan view of a machine in which'the instant invention is embodied. with parts broken away; i

Rig. 2 is .a longitudinal vertical section taken along the line 6-6 in Fig. 4, with parts broken substantially along the broken line 2-2 in Fig. 1, with parts broken away;

Fig. 3 is a transverse vertical section taken substantially along the line 33.in Fig. 2, with parts broken away;

Figs. 4 and 5 are transverse vertical sectional views taken substantially along the lines 4-4, 55, respectively, in Figs. 1- and 2, with parts broken away; i

Fig. 6 is horizontal section taken substantially away; I

Fig. 7 is an enlarged sectional viewshowin the staple which holdsthe container parts together and also showing portions of the machine immediately adjacent the staple, with parts broken.

' drawings illustrate a staple detector and con- 'tainer part stacking mechanism used in a machine for securing closure elements A (Fig. l) to container or can end members B with metal wire staples C to provide a .unitarycan top D for the well known fibre milk containers disclosed in United States Patent 2,085,979, issued July 6, 19 37 to J. M. Hothersall.

In the machine these unitary can tops D are propelled along a straight line path of travel be tween spaced and parallel guide bars II by a reciprocating feed bar I2 located in aslideway [3 formed in'a runway plate l4 secured to the top of a frame I 5 which may constitute the main frame of the machine. The feed bar may be reciprocated in any suitable manner in time with the other moving parts of the machine. feed dogs '6 located at spaced intervals lengthwise of the bar engage'behind the can tops and advance them in anintermittent or step-by-step manner.

During the advancement of these can tops D through the machine they are momentarily brought to rest at a testingstation E (Figs. 1, 2,

4, -6 and '7). At this station a test is'made to ascertain if the closure element A and the end member B are properly stapled together. The testis made by an electric detector device which includes a vertically movable detector slide2 I The detector slide 2| is preferably rectangular incross section and moves in a vertical slideway 22 formed in the .plate M. The bottom of the slide is flat and rests on ablock 24 mounted on acrank 25 of a shaft26 carried in bearings 21 Secured to the main frame 15. The shaft is Spring held rocked through a partial rotation in one direction and thence in an opposite direction during each cycle of the machine, i. e., for each advancement of a can top D.

The rocking of the shaft 26 is brought about by a segment gear 28 (Figs. 2 and 3) which is carried on the shaft. The gear meshes with a rack 29 which slides in a rectangular bearing 3| formed in the main frame l5.

may be actuated in time with the other moving parts of the machine.

Screws 35 secured in the runway plate I4 and having heads 36 which operate within elongated clearance recesses 31 in the slide 2|, retain the slide in its slideway. Spring barrels 38 in bores 39 in the slide engage against the plate l4 and thus press the slide down against the crank 24, see also Fig. 4.

Hence when the shaft 26 rocks in one direction, the crank block 24 pushes the slide 2| upwardly toward the can top D in the runway for the testing operation. Conversely, when the shaft rocks in the opposite direction the crank block 24 moves down and the spring barrels 38 in the slide push the latter down and away from the can top.

Testing for the staple C in the can top is preferably done electrically. For this purpose the slide 2| carries on its top surface an insulator 42 (Figs. 2, 4 and 6) in which there are imbedded a pair of electric testing contacts 43. 44. The insulator is secured in place by a screw 45. The contacts are located in vertical alignment with the bent under ends of the staple C. as best shown in Figs. 6 and '7. These contacts are connected with flat spring wires 48, 49 which extend beyond the confines of the insulator 42 and project through a slot in the side of the runway plate l4.

The contact wires 48, 49 terminate in a casing 52 which is secured to a side of the runway plate M. The ends of the wires are formed with movable contacts 54, 55 which are normally out of engagement but in vertical alignment with the inner ends of a pair of stationary contacts 56, 51. These contacts 56, 51 are secured to an insulating block 58 in the casing and are connected with a pair of lead wires 6|, 62 which form a portion of certain electric circuits which will be hereinafter explained in connection with the wiring diagram in Fig. 8.

Hence when the slide 2| moves up into testing position it brings the movable contacts 54. 55 into engagement with the stationary contacts 56, 51 in the casing 52 and thereby connects the testing contacts 43, 44 with a source of electric current. Simultaneously with this action the slide brings the testing contacts into engagement with the opposite ends of the staple C in the can top D if there is such a staple in place. During this engagement the can top is held against dis-- placement by an overhanging anvil 65 of insulating material which backs up the sta le C and which is secured to one of the guide rails The staple C thus engaged by the two testing contacts 43, 44 bridges the gap between them and thereby becomes a portion of the testing circuit of control devices hereinafter explained. If the staple C is in proper place in the can top and is not broken, the tested top is advanced to a stacking station F. This advancement is made after the slide 2| has moved down and is emac- The rack may. be reciprocated. in any suitable manner, such as for example, by a link 32 and a lever 33 which tive upon the next advancing stroke of the feed bar l2.

The stacking station F (Figs. 1, 2 and 5) is adjacent the testing station E and is spaced therefrom one step of advancement of the can tops D moving along the runway. The stacking devices at this station include a lifter 15 which is disposed below the path of travel of the can tops moving along the runway and which is retained for vertical movement in a slide recess 16 formed in the main frame l5 and within a clearance recess 11 cut in the runway plate M.

The top of the lifter I5 is normally flush with the runway so that the can tops D may readily pass from the runway to the lifter. The top surface of the lifter is formed with a clearance slot E8 to clear the plug section of the closure element A and is further provided with a clearance'slot 19 for the feed bar l2.

Hence when the feed bar |2 moves through an advancing stroke following a testing operation, one of its feed dogs It removes a tested can top D from the testing station E and advances it into the stacking station F. A can top so advanced is received on top of the lifter l5 preparatory to being raised into a magazine located above the lifter if the test has determined a properly stapled can top or preparatory to being discharged from the machine if such properly stapled can top is absent.

The lifter '15 is shifted vertically in its slide recess 16 by a cam 8| which is mounted on the rock shaft 26. The cam is located in an opening 32 formed in the lifter and bears against a hardened plate 83 secured to the lifter adjacent the bottom of the opening. The shaft extends through vertical slots 84 in the'sides of the lifter and these slots permit vertical movement of the latter.

The lifter 15 is forced upwardly against the cam 8| by a plurality of compression springs 86' which are located below the lifter. These springs are retained in vertical pockets 8'! formed in a bracket 88 which is bolted to the main frame l5. The upper ends of the springs v engage in shallow seats 89 formed in the bottom of the lifter.

Hence when the rock shaft 26 revolves through a partial rotation to move the testingslide 2| into testing position, it also rocks the cam 8|. The shaft and the cam rotate in a clockwise direction as viewed in Fig. 5 during this up-stroke and this bring a flat side 9| of the cam into spaced relation above the hardened plate 83 of the lifter. This shifting of the cam permits the compression springs 86 to raise the lifter and the can top D carried thereon.

The raising of the lifter 15 carries the can top D upwardly above its path of travel in the runways and into a magazine generally indicated by the numeral 92. This magazine. includes a plurality of vertical rods 94 (Figs. 1, 2 and 5) which have their lower ends secured in a base 95. The base is bolted to the top of the runway plate M. A can top entrance slot.9$ and a discharge slot 91 are, formed in the base in line with the path of travel of the can tops through the machine. I

The base 95 also carries a plurality of vertically disposed can top supporting fingers I01 (Fig. 5) which are located in recesses I02 formed in the base adjacent the path of travel of a can top as it enters the stacking station. 7 These fingers are mounted on pivot pins I03 which are carried in suitable bearings formed in the obtained,

by the lifter 15 it pushes past the spring held' fingers IN and is elevated to a position slightly above the upperends of the fingers. The fingers snap back into their original position assoon as the can top passes and hence when the lifter moves down thecan top, which is now within the magazine, moves down as far as the tops of the fingers and is thereafter supported on the fingers. In this manner as each new can top is elevated into the magazine it is placed beneath the others already in the magazine and hence a vertical stack is readily built up.

Only unitary can tops D which are properly stapled together, are stacked in the magazine 92. It'ya staple C is broken or has been partially or entirely omitted from the assembled parts of a can top D when it is tested at the testing station E, this constitutes an abnormal or imperfect can top. Such a top is prevented from being stacked into the magazine 92 and is subsequently discharged from the machine, as will now be described.

Discharge of an abnormal can top D is brought about by holding the lifter 15 against movement when such a can top is advanced into position on the lifter. For thispurpose the lifter is formed with a depending vertical stem III (Figs. 2 and 5) which extends down through a bearing II2 formed in the bracket 88. Anotch H3 is cut in thelower end of the stem where it is disposed adjacent a beveled surface I14.

Adjacent the notched lower end of the stem 3 I I! there is a small bell crank lever I lfimounted on a pivot pin II1carried in a pair of spaced lugsv II8 formed on an arm extension N9 of the bracket 88. The bell crank is formed with a substantially horizontal leg IN and with a vertical leg I22 which "extends up alongside the stem II-I, terminating in a hook I23 disposed in,

alignment with the'notch '-I I3 when the lifter is in its lower position. The horizontal leg *I2I 0f the bell crank engages against a spring barrel unit I25 located in a boss I26 on thebracket extension. This spring barrel maintains the leg [22in engagement with the inner end of a horizontally movable core I31 of a latch solenoid I32 secured to the bracket 88. The core is adapted to be projected toan outward position by a compression spring located within the solenoid when the latter is'deenergized.

The solenoid I32 is normally maintained eners g'ized and thus the core I3I is normally drawn in against the resistance of its spring. This normal. position maintains th hook I23 of the bell crank U6 out of engagement'with the notch II3 of the lifter stem. II I, under which conditions nor-. mat. raising and lowering of the lifter 15 is 'When an abnormal can top is moved onto the lifter, the solenoid I32 is lie-energized. This tie-energizing of the solenoid permits the solenoid spring to thrustthe core toward the lifter stem H I and this rocks'the-bell crank H6 against the resistance of its spring barrel unit I25. Such a rocking-of the bell crank brings the hook I23 into engagement with the notch I I3 in the lifter ing station F and places it on top 'of the stem" I I1 and thereupon the lifter :15 'locked against movement. i

Hence when the shaft 26 rockszin one direction to raise the testing slide 21 into testingposition against a can top 1) at rest in the testing station E, the resulting movement of the lifter cam BI on the shaft has no effectaon thelocked 15 at the stacking station F to permit springs 86 to function and the lifter thereforeremains stationary. Hence the abnormal or imperfect can top located on the lifter at station .F is prevented from being stacked into the. magazine. with the properly stapled can tops. I When the shaft 26 rocks in the opposite dime-i tion to pennit the testing slide 21' to movedownwardly away from the can top D at the testing station; the lifter cam BI is simultaneously This action depresses the lifter stem sufficientto disengage the "bell'crank hook I23 from the: lifter stem notch I I3. 'If the can "top just tested is a good one the solenoid is again energized and thus the hook I23 will be moved back with the solenoid core and thereby release the stem and the lifter for the next stacking movement.

However; the lifter cam BI holds the lifter 15 depressed until the feed bar I2 moves through its advancing stroke and returns again. Durin this advance stroke 'the forward feed dog I6 on the bar engages behind the abnormal can topon the lifter and pushes it out of "the machine through the slot 91in the magazine base 95. The abnormal can top falls to any suitable place of deposit. i

On this same stroke,the feed bar "advances the newly tested can top at station E to'the stack- If this can top was tested as a good top it will be stacked into the magazine by the lifter on, its next up stroke a hereinbeforeexplained. If it is an abnormal top the lifter will be pre vented from raising as just explained.

Reference should now be had to the wiring diagram in Fig. 8. The energizing and "de-energizingof the latch solenoid I32 is brought about by a plurality Of operating and holding circuits which will now "be explained.

The first of these circuits is an operating circuit K which includes a cam actuated timing switch I5I a triple contact relay switch I52 having a normally closed contact I53 and a pair of normally open contacts I54, I55 and a relay solenoid I56 of a relay switch I51 havinga pairof normally open contacts I58, I 59. The win er the timing switch I5I may be actuated in any suitable manner in time with'the operating parts of the machine.

The timing switch I5I is maintained closed for approximately seven-eighths of every cycle of the machine. During this normally closed period of the switch, electric energy from a suitable source of power, such as a generator IGI passes along the circuit as follows, from the generator along a main lead wire I 62, a wire I63,*closed timing switch I5I, wires I64, I65, through the closed contact I53 of the triple contactswitc'h I52, along a wire I66, through the relay solenoid I56. a wire II 61, and thence back to the genera tor along'a return wire I 68. Electric energy flow ing along this circuit energizes the relay solenoid I56. 1

Energizing of the relay solenoid I56 of relay switch I51 closes its two normally open contacts I58, I59 to form parts of two new circuits Land M. Circuit L is a holding circuit for maintaining the relay solenoid I56 energized. This circuit receives electric energy from the timing switch wire I64 of operating circuit K. The energy passes along a wire I1I which connects with wire I64, through closed contacts I56 of the switch I51, along a wire I12 connecting with I the relay solenoid I56, through the solenoid I56,

and thencaalong wires I61, I68 which return to the generator. This holding circuit cuts out the normally closed contacts I53 of the triple contact switch I52.

The circuit M is not yet complete and reference to it will be passed over for the time being.

When the holding circuit L is established a new operating circuit N is formed. This operating circuit N includes a normally open auxiliary tim ing switch I15 and a relay solenoid I16 of the triple contact switch I52. The auxiliary timing switch I15 is cam operated in any suitable manner in time with the moving parts of the machine. This timing switch is normally open for approximately fifteen-sixteenths of every cycle of the machine and is closed for only one-sixteenth of the cycle.

During the period when the auxiliary timing switch I15 is closed the operating circuit N is complete and electric energy flows from the generator wire I62 along a connecting wire I18, closed timing switch I15, connecting wires I19, I8I, through the relay I16 of the triple contact switch I52, and returns to the generator along a wire I82 and the return wire I 68. Electric energy passing along this circuit energizes the relay solenoid I16. Energizing of the solenoid moves the triple contact switch I52 and thus opens its normally closed contacts I53 and closes the two normally open contacts I54, I55.

Closing of the normally open contact I54 of the triple contact switch I 52 establishes the holding circuit M hereinbefore mentioned' This circuit M holds the relay solenoid I16 energized so that the auxiliary timing switch I15 may open breakingthe operating circuit N VifithOllt affecting the solenoid. This holding of the solenoid is brought about by energy which is received from the generator lead wire I62 and which flows through the closed contacts I59 of the double contact switch I51, along a wire I85, closed contacts I54 of the triple contact switch I52, a wire I86, wire I8I, relay solenoid I16, and return wires I82, I68.

Closing of the normally open contact I55 of the triple contact switch I52 completes a latch solenoid circuit P which includes the latch solenoid I32. Electric energy for this circuit is received from the generator wire I62 and flows along a connecting wire I9I, closed contacts I55 of the 1 triple contact switch I52, a wire I92, latch solenoid I32, a connecting wire I93 and return wire I68. Energy flowing along this circuit maintains thelatch solenoid I32 energized. I

Now it will be readily seen, from an inspection of the wiring diagram. that the maintenance of the latch solenoid I32 in a normally energized condition depends solely upon maintaining the holding circuit L closed, such circuit including the relay solenoid I56 of the double contact switch I51. The maintenance of the relay solenoid I56 in an energized condition depends in its turn upon the main timing switch II in the operating circuit K.

In the operation of testing the can tops D for the presence of staples C as hereinbefore described, the main timing switch I5I is operated in conjunction with the testing contacts 43, 44 of the detector slide 2I as will'now be explained.-

With the main timing switch I5I closed and the latch solenoid I32 energized, the detector slide 2| moves up toward a can top D at the testing staholding circuit L. In other words, if a staple C- is in place in the top D and is not broken, when the timing switch is opened, electric energy passes from the generator wire I62, along wire 6 I, closed contacts 56, 54, wire 48, contact 43, staple C, contact 44, wire 49, closed contacts 55, 51, wire 62, then along wire I1I, closed contacts I58 of the double contact switch I51, wire I 12, relay solenoid I56, and return wires I61, I68.

Thus the holding circuit L is maintained closed during the time the testing contacts 43, 44 are in engagement with the perfect staple C and when the timing switch I5I is open. Before the testing contacts 43, 44 are withdrawn from the staplev by the lowering of the detector slide 2|, the timing switch again closes. Hence the other holding circuit M and the latch solenoid circuit P are maintained closed and this keeps the latch sole-. noid in an energized condition.

It is this holding action of the circuits through the staple C that holds the latch lever II6 away from the lifter 15 and thus permits the lifter to stack these good can tops D into the magazine, as hereinbefore described. As long as can tops with good staples are passing through the detector station, the holding circuits remain closed and hence the latch solenoid remains energized.

However, if the staple C is broken or is entirely, missing from the can top D when the testing contacts 43, 44 come into position against it, electric energy is interrupted when the timing switch I5I opens, the holding circuit thus being broken. This de-energizes the relay solenoid I56 and permits the two contacts I58, I59 of the double con tact switch I51 to open and the holding circuit M is broken also.

Breaking of circuit M permits the triple contact switch I52 to operate and its contacts I54, I55 open, while reclosing its contact I53. Thus the latch solenoid circuit P is broken and the latch solenoid I32 is de-energized. It is this deenergizing action on the latch solenoid that locks the lifter 15 against movement.

' The closing of the timing switch I5I immediately following the detection of an abnormal can top D recloses the operating circuit K and thus reestablishes the holding circuit L. However, the closing of the auxiliary timing switch I15 to re-. establish the holding circuit M and latch solenoid circuit P- is delayed until that part of the cycle of the machine is reached when the lifter is at the bottom of its stroke as when its operating.

= const1'uction and arrangement of the parts; with- ;eutdeparting from the spirit and scope of the-in- V. vention or sacrificing all of itsmaterial advantages, '-the form hereinbefore described being merely apreferred embodiment thereof.

claim: a 1,111; a detecting and stacking mechanism for fibre container parts each secured togetherwith an electric current conducting, wire staple, the

combination of feeding devices for advancing container parts along a predetermined path of travelthrough a plurality of stations, a movable, .staple detector elementdisposed at one ,station and having spaced. electric current con iductin-g portions engageable with spaced portions of said; staple for conducting: anelectric current --thereth1=m1;gh, means for moving, said detector selementtoward and away from a container part tobe-testeda magazine at anotherstation for receiving container parts having staples properly positioned'therein, a stacking device disposed in vertical alignment with said magazine and having means for moving the same toward and away from said magazine for elevating per fectly stapled container parts thereinto, actuating means for vertically reciprocating said stacking device towards and away from said magazine, a normally inactive latch device disposed adjacent said stacking device, and electric instrumentalities connecting with the spaced current conducting portions of said detector element also connecting with said latch device, said instrumentalities being operable" when an electric circuit is completed to actuate said latch device to hold it in inactive position to render the stacking device operative upon the detection of a perfect container part, and operable when the detector element fails to complete a circuit to render the latch device active so as to hold the stacking device inoperative when a staple is misspart will be discharged from the mechanism by continued operation of said feeding devices.

3. In a. detecting and stackingzmechanism for spaced portions of, said staple to' conduct an electric current theretln'eugh, a magazinedisposed adj acentsaidi detector element, a vertically movable stacking element disposed in vertical alignment with said magazine for elevating container [parts havingl properly positioned staples into ing or broken, whereby such improperly stapled container part will be prevented from being elevated into said magazine and will be discharged from the mechanism by further operation of said feeding devices.

2. In a detecting and stacking mechanism for fibre container parts each secured together with an electric current conducting wire staple, the combination of a support for a container part to be tested, a vertically movable staple detector element arranged adjacent said support and having spaced electric current conducting portions engageable with opposite ends of said staple for conducting an electric current through the staple, a magazine for container parts disposed adjacent said detector element, a vertically movable stacking element arranged below said magazine for lifting properly stapled container parts received thereon into said magazine, feeding devices for shifting the container parts from said detector element to said stacking element, actuating means for raising and lowering said detector and stacking elements simultaneously to test a container part while a previously tested properly stapled container part is stacked into the magazine, and electrically controlled instrumentalities responsive to an electric circuit connected with said spaced detector element current conducting portions and operable to hold the stacking element inoperative when such staple is missing or broken, whereby such improperly stapled container part will be prevented from being deposited in said magazine after being shifted from the detector element to the stacking element so that said improperly stapled said magazine, actuating means for elevating said stacking; element, a normally inoperative latch device disposed adjacent said stacking element, devices for shifting said.- latcli device into and out of: holding engagement with said stacking element, electro-mechanical means including electric circuits connected with the spaced stapleengagingmean of saidqdetector element and operative-int the absence of an electric current conducting circuit through said staple to shift said latch device into holding engagement with the stacking element to render the same inoperative when a staple is missing and when a staple is broken, thereby preventing improperly stapled container parts from being elevated into said magazine, andmeans movable in one direction to elevate said detector element fora detecting operation, said means when moved in the opposite direction, depressing said stacking element relative to said magazine.

4. In a detecting and stacking mechanism for fibre container parts each secured together with an electric current conducting wire staple, the combination of a support for a container part to be tested, a vertically movable detector element having spaced electric current conducting portions engageable with opposite end of a staple properly positioned in said container part, a shaft for moving said detector element towards and away from said container support, actuating means for rocking said shaft, a magazine disposed adjacent said detector element, a vertically movable and yieldable stacking element disposed below said magazine for lifting properly stapled container parts received thereon into said magazine, a cam on said shaft and engaging against said yielding stacking element for operating the same,

and electrically controlled instrumentalities responsive to an electric circuit connected with said spaced detector element current conducting portions and operable to hold the stacking element inoperative against the action of its operating cam when a staple is missing or broken so that such improperly stapled container part will be prevented from being deposited in said magazine and will be discharged from the mechanism by said feeding devices.

5. In a detecting and stacking mechanism for composite fibre container parts each secured together with an electric current conducting wire staple, the combination of a support for the container part to be tested, a staple detector element arranged adjacent said support and having spaced electric current conducting portions engagea'ble with opposite ends of said staple for conducting an electrical current through the staple,

a magazine for container parts disposed adjacent said support, a normally active reciprocating stacking element arranged adjacent said magazine for moving properly stapled container parts into the magazine, feeding devices for shifting the container parts from said detector element to said stacking element, means for reciprocating said stacking element through a stacking stroke and thence through a return stroke, and electrically controlled instrumentalities including a normally closed electric circuit connected with said detector element current conducting portions for controlling movement of said stacking element and operable when said electric circuit is broken by the detection of an imperfect container part by said detector element to hold said stacking element, against movement through a stackin stroke to prevent stacking of such imperfect container part when a staple is missing or broken therein.

6. In a detecting and stacking mechanism for fibre container parts each secured together with an electric current conducting wire staple, the combination of a movable staple detector element having spaced electric current conducting portions engageable with spaced portions of said staple for conducting an electric current therethrough, a magazine for receiving container parts, a normally reciprocatin stacking device disposed in alignment with said magazine for moving detected container parts into said magazine, a latch device positioned adjacent said stacking device and having engagement there with only when an imperfect container part is detected to hold the same inoperative, and instrumentalities including a normally closed electric circuit connected with the spaced current conducting portions of said detector element and with said latch device to hold the latter out of engagement with said stacking device so long as current flows through properly positioned and unbroken staples to maintain said stacking device operative to stack all such perfect container parts into said magazine, said latch device being operative to prevent reciprocation of said stacking device when a missing or broken staple interrupts the passage of electric current through said instrumentalities.

NICHOLAS PELOSI. 

